With the widespread of intelligent operating systems, demands of users for various software application programs (hereinafter “applications” or “apps” for short) grow on a daily basis. A mobile terminal device operated by an intelligent operating system may generally have many different applications being installed therein or as built-in applications, from which a user may operate these different applications. Generally, when an application is started or launched, a window of the application is displayed in a full-screen manner on a display area of a screen of the mobile terminal device. When another application is subsequently launched, a window of the subsequently launched application will cover the window of the previously launched application in the full-screen manner on the display area of the screen of the mobile terminal device, thereby making the previously launched application invisible.